Hey everyone,

I'm trying to do some research on how much horsepower everyone is running while still running Mivec. I've tried searching for this information, but I can't find anything definitive which isn't reassuring -

My basic question - can Mivec be used (in a meaningful way) on high horsepower cars with big cams, high RPMs, and heavy springs? Specifically, can Mivec advance and retard the cam accurately and maintain those movements continuously whenever you're applying 90 pound springs behind it on 280* cams? Additionally, whenever you start adding up all of these factors and then throw oil pressure/volume on top of that for higher revving applications are there any additional concerns? Is there some power level, RPM level, cam size, spring pressure, etc... that Mivec is no longer effective and could in fact be detrimental (i.e. cam moving without total control)?

I hope that my question makes sense and hopefully maybe there will be some real responses/real world experiences to clear up my concerns.

Thanks!

 

No issues I've seen with control on my dsm that has the evo9 mivec setup adapted. I've run as much as about 145-150lb on the seat testing parts and fp11r cams. The highest I've had it is 10,400rpm. Control works fine with the haltech, I suspect the stock ecu controls would still be fine as well though, I haven't had to do anything weird.

 

Thanks for the response! Of all of the possible responses on EvoM, you have to be one of the best people to receive that sort of an explanation and real world experience from. I appreciate it. Based on your working knowledge of the valvetrain and head(s) from Evos/DSMs, I'm going to go ahead and plan on maintaining my Mivec setup through my next build now.

I'll be running an AEM EMS, so I'm hoping that I won't have any issues with a 280 cam and Mivec from a tuning perspective either - I've been looking at your 12 tooth setup as well for my car to help out with the AEM. Are you running the stock Mivec cam gear with an adjustable exhaust cam gear or do you have some form of a modified stock Mivec gear (or ACL/Greddy)? Also, do you suspect with your HLA regulator and everything else being relatively "stock" in oiling that everything will be safe for controlling the Mivec gear at 9,500 rpms with large lift/spring pressure? I know you've responded to this indirectly, but I'm not certain what modifications your setup may have to oiling that may improve Mivec control versus a stock 9. Sorry - I know that's a bit of an evolution of the original question you've answered. Thank you though for your assistance! I really appreciate it!

 

For what is worth

Mivec evo 9
GSC R2 cams (274)
AEM series 2
AEM adjust ex cam
Modified trigger disk (triggerdisk.com)
2.4 , EFR 9180
850hp

All done by English Racing, Mivec is working great spool is insane for a 800hp evo.

 

I'm running a modified oem mivec gear with about 46deg travel. I feed oil directly off the oil filter housing but with a -4an oil filter inline. I suspect the oem evo9 setup with the feed off the main gallery in the block works just as well or maybe even better. When I had low pressure the only time it would have slow response and minor control issues was down at idle and really low rpm or if I held it against a stop for a while it would respond slowly. After you are in the operating range though, I think it acts more like a couple of hydraulic check valve pressure chambers with just a lot of leakage. The leakage becomes the oil for the journal bearing. The feed pressure doesn't hold it in place or really even force the cam to move. The opening and closing events really help drive that and the control system lets it move while the feed supply backfills the other side.

All in all, it is a pretty robust system in general and I think you will be just fine. I suspect problems at lower rpm would be worse than high rpm just because of more oil bleed time to leak and change angle per revolution.